Author: Hon A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand, 1997. Updated by Dr Ebtisam Elghblawi, Tripoli, Libya, April 2017.
Alpha hydroxy acids or AHAs are a group of organic carboxylic compounds including glycolic acid (from sugar cane), citric acid (from citrus fruit), lactic acid (from milk and pickled vegetables), malic acid (from apples) and tartaric acid (from grapes).
Glycolic acid and lactic acid are often used in cosmetics to rejuvenate the skin.
Alpha hydroxy acid preparations are recommended for those whose skin is showing signs of ageing. Fine lines, brown marks and dry spots (actinic keratoses) can improve with regular applications or peels. Glycolic acid may also prove helpful for those prone to acne. It is safe in pregnancy.
With time and sun exposure there is a gradual but slow-down in the rate at which old cells leave the surface of the skin and are replaced by newer cells. This results in a surface layer of dead skin cells that are responsible for the appearance of aged skin. Alpha hydroxy acids encourage the shedding of old, sun-damaged surface skin cells.
They loosen the glue-like substances that hold the surface skin cells to each other, therefore allowing the dead skin to peel off gently. The skin underneath has a fresher, healthier look with a more even colour and texture.
With high concentration and long-term use, alpha hydroxy acids may also affect the deeper layers of the skin. Collagen and elastin regenerate making fine lines less obvious.
Alpha hydroxy acid peels are an ideal treatment for busy people who are unable to take time off work for a deeper peel or laser resurfacing. They gently retexture the skin over a period of a few months. The treatments are also helpful in stabilising oily or acne-prone skin and improving skin tone.
A glycolic acid peel takes about 15–20 minutes. It is usually repeated at one to two weekly intervals as it is superficial so recovery is rapid. It The strength of each peel ranges from 20 - 70%, depending on skin sensitivity and starting gently.
The face is cleansed thoroughly and then the peel solution is applied for three minutes. It stings mildly. The solution is then washed off.
Treated skin may be a little pink immediately after treatment. A little peeling may occur over the next few days. It can be disguised with moisturiser or normal make-up.
There are many products with varying concentrations of various alpha hydroxy acids in differing bases. For the best results, leave-on preparations should be applied at night, if necessary twice daily. They can be alternated with other anti-aging preparations including retinoid creams and vitamin C.
There are specific preparations for dry, normal and oily skin. Those available from medical practitioners are stronger than those at pharmacies and beauty therapists.
Don't forget the most important skin care tip — always protect your skin from the sun!
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